
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>鼠标移过，改变图片路径</title>
<style>
body,ul,li{margin:0;padding:0;}
body{background:#000;}
img{border:0;border-radius:3px;}
ul{list-style-type:none;}
#box{width:212px;border:5px solid #fff;overflow:hidden;zoom:1;background:#fff;border-radius:5px;margin:10px auto;padding:0 0 3px 3px;}
#box li,#box li img{float:left;width:50px;height:50px;}
#box li{margin:3px 3px 0 0;}
#box li.first{position:relative;}
#box li.first,#box li.first img{width:156px;height:156px;}
    
    /* 用来加载图片，加载过程图片会有半透明效果 */
/*    除了 position: absolute;和 position: fixed;会直接将元素从排版中拿走从而脱离文档流之外，设置float对象也会 “打乱这个排列”从而也被称为脱离文档流。*/
#box li.first div{position:absolute;top:0;left:0;width:156px;height:156px;display:none;opacity:0.5;filter:alpha(opacity=50);background:#fff url(img/loading.gif) 50% 50% no-repeat;}
</style>
<script type="text/javascript">
window.onload = function ()
{
	var oImg = document.getElementById("box").getElementsByTagName("img");
	var oDiv = document.getElementsByTagName("div")[0];
	for (var i = 1; i < oImg.length; i++)
	{
		oImg[i].onmouseover = function ()
		{						
			var img = new Image();
			img.src = oImg[0].src = this.src.replace(/small/,"big");
            
			oDiv.style.display = "block";
            /*complete 属性可返回浏览器是否已完成对图像的加载*/
			img.complete ? oDiv.style.display = "none" : (oImg[0].onload = function() {oDiv.style.display = "none"})
		}	
	}
};
</script>
</head>
<body>
<ul id="box">
    <li class="first"><img src="img/big_1.jpg"><div></div></li>
    <li><a href="javascript:;"><img src="img/small_1.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_2.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_3.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_4.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_5.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_6.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_7.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_8.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_9.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_10.jpg"></a></li>
    <li><a href="javascript:;"><img src="img/small_11.jpg"></a></li>
</ul>
</body>
</html>